New alloys are as mouldable as plastic and stronger than steel

Material scientists at Yale University have developed metal alloys that are easily mouldable

and yet stronger than steel. The new materials cost around the same as high-end steel, but

can be processed as cheaply as plastic.

The bulk metallic glasses (BMGs), developed by a team led by Jan Schroers, have a random

atomic structure, as opposed to the orderly, crystalline structures found in conventional

metals. This means that they can be "blow moulded" (in the same way that plastics are) into

very complex shapes that can't be achieved using regular metal, without losing any of their

strength or durability.

Blow moulding is a process used to make hollow plastic parts which involves heating the

material and then forming it into a mould using air pressure.  The new alloys required low

temperatures and low pressure to soften and mould, as well as allowing the team to combine

three separate steps in traditional metal processing (shaping, joining and finishing) into a

single step, saving time and labour costs. The findings were announced in the journal

Materials Today.

The team has demonstrated the mouldability of the metals by creating complex shapes like

seamless bottles, watch cases and biomedical implants that can be moulded in less than a

minute and are twice as strong as typical steel.

The BMGs are made up of a range of materials, including nickel, titanium, copper and

zirconium (which is used in dentistry). The team is already using the materials to create

tiny resonators for microelectromechanical systems.

Schroers said in a press release: "This could enable a whole new paradigm for shaping metals.

The superior properties of BMGs relative to plastics and typical metals, combined with the

ease, economy and precision of blow moulding, have the potential to impact society just as

much as the development of synthetic plastics and their associated processing methods have in

the last century."